how call function from other file

[kucingkucing]

hi. I like to create a mod to auto eat one edible item on one of the slots when Geralt health is under 100%.
this is the code

// if player health under 100% and curently do not consume any food
if( thePlayer.GetStatPercents(BCS_Vitality) < 1 && !FactsDoesExist("consumed_food_cnt") )
{
	//comsume potion or foods or alcohol drinks
	DrinkPotionFromSlot(EES_Potion1);
}

note : the "DrinkPotionFromSlot" is from "content\content0\scripts\game\player\playerWitcher.ws" line 4493

the problem I have is:
1. I do not have any idea where I should put the code so it can be run at any time?? (in exploration OR in combat . are high priority)
2. the "DrinkPotionFromSlot" function is part of "playerWitcher.ws", is there any way to call it from "modNAME\content\scripts\local" OR other folder??

thank you for reading,

any info, tips, link, google or anything. I will appreciate it